layout/style/MediaQueryList.h@925c144e1f1f (annotated)
layout/style/MediaQueryList.h
Fri, 16 Jan 2015 18:13:44 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Fri, 16 Jan 2015 18:13:44 +0100
- branch
- TOR_BUG_9701
- changeset 14
- 925c144e1f1f
- permissions
- -rw-r--r--
Integrate suggestion from review to improve consistency with existing code.
| michael@0 | 1 | /* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */ |
| michael@0 | 2 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | /* implements DOM interface for querying and observing media queries */ |
| michael@0 | 7 | |
| michael@0 | 8 | #ifndef mozilla_dom_MediaQueryList_h |
| michael@0 | 9 | #define mozilla_dom_MediaQueryList_h |
| michael@0 | 10 | |
| michael@0 | 11 | #include "nsISupports.h" |
| michael@0 | 12 | #include "nsCycleCollectionParticipant.h" |
| michael@0 | 13 | #include "nsAutoPtr.h" |
| michael@0 | 14 | #include "nsTArray.h" |
| michael@0 | 15 | #include "prclist.h" |
| michael@0 | 16 | #include "mozilla/Attributes.h" |
| michael@0 | 17 | #include "nsWrapperCache.h" |
| michael@0 | 18 | #include "mozilla/dom/MediaQueryListBinding.h" |
| michael@0 | 19 | |
| michael@0 | 20 | class nsPresContext; |
| michael@0 | 21 | class nsMediaList; |
| michael@0 | 22 | |
| michael@0 | 23 | namespace mozilla { |
| michael@0 | 24 | namespace dom { |
| michael@0 | 25 | |
| michael@0 | 26 | class MediaQueryList MOZ_FINAL : public nsISupports, |
| michael@0 | 27 | public nsWrapperCache, |
| michael@0 | 28 | public PRCList |
| michael@0 | 29 | { |
| michael@0 | 30 | public: |
| michael@0 | 31 | // The caller who constructs is responsible for calling Evaluate |
| michael@0 | 32 | // before calling any other methods. |
| michael@0 | 33 | MediaQueryList(nsPresContext *aPresContext, |
| michael@0 | 34 | const nsAString &aMediaQueryList); |
| michael@0 | 35 | private: |
| michael@0 | 36 | ~MediaQueryList(); |
| michael@0 | 37 | |
| michael@0 | 38 | public: |
| michael@0 | 39 | NS_DECL_CYCLE_COLLECTING_ISUPPORTS |
| michael@0 | 40 | NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(MediaQueryList) |
| michael@0 | 41 | |
| michael@0 | 42 | nsISupports* GetParentObject() const; |
| michael@0 | 43 | |
| michael@0 | 44 | struct HandleChangeData { |
| michael@0 | 45 | nsRefPtr<MediaQueryList> mql; |
| michael@0 | 46 | nsRefPtr<mozilla::dom::MediaQueryListListener> callback; |
| michael@0 | 47 | }; |
| michael@0 | 48 | |
| michael@0 | 49 | typedef FallibleTArray< nsRefPtr<mozilla::dom::MediaQueryListListener> > CallbackList; |
| michael@0 | 50 | typedef FallibleTArray<HandleChangeData> NotifyList; |
| michael@0 | 51 | |
| michael@0 | 52 | // Appends listeners that need notification to aListenersToNotify |
| michael@0 | 53 | void MediumFeaturesChanged(NotifyList &aListenersToNotify); |
| michael@0 | 54 | |
| michael@0 | 55 | bool HasListeners() const { return !mCallbacks.IsEmpty(); } |
| michael@0 | 56 | |
| michael@0 | 57 | void RemoveAllListeners(); |
| michael@0 | 58 | |
| michael@0 | 59 | JSObject* WrapObject(JSContext* aCx) MOZ_OVERRIDE; |
| michael@0 | 60 | |
| michael@0 | 61 | // WebIDL methods |
| michael@0 | 62 | void GetMedia(nsAString& aMedia); |
| michael@0 | 63 | bool Matches(); |
| michael@0 | 64 | void AddListener(mozilla::dom::MediaQueryListListener& aListener); |
| michael@0 | 65 | void RemoveListener(mozilla::dom::MediaQueryListListener& aListener); |
| michael@0 | 66 | |
| michael@0 | 67 | private: |
| michael@0 | 68 | void RecomputeMatches(); |
| michael@0 | 69 | |
| michael@0 | 70 | // We only need a pointer to the pres context to support lazy |
| michael@0 | 71 | // reevaluation following dynamic changes. However, this lazy |
| michael@0 | 72 | // reevaluation is perhaps somewhat important, since some usage |
| michael@0 | 73 | // patterns may involve the creation of large numbers of |
| michael@0 | 74 | // MediaQueryList objects which almost immediately become garbage |
| michael@0 | 75 | // (after a single call to the .matches getter). |
| michael@0 | 76 | // |
| michael@0 | 77 | // This pointer does make us a little more dependent on cycle |
| michael@0 | 78 | // collection. |
| michael@0 | 79 | // |
| michael@0 | 80 | // We have a non-null mPresContext for our entire lifetime except |
| michael@0 | 81 | // after cycle collection unlinking. Having a non-null mPresContext |
| michael@0 | 82 | // is equivalent to being in that pres context's mDOMMediaQueryLists |
| michael@0 | 83 | // linked list. |
| michael@0 | 84 | nsRefPtr<nsPresContext> mPresContext; |
| michael@0 | 85 | |
| michael@0 | 86 | nsRefPtr<nsMediaList> mMediaList; |
| michael@0 | 87 | bool mMatches; |
| michael@0 | 88 | bool mMatchesValid; |
| michael@0 | 89 | CallbackList mCallbacks; |
| michael@0 | 90 | }; |
| michael@0 | 91 | |
| michael@0 | 92 | } // namespace dom |
| michael@0 | 93 | } // namespace mozilla |
| michael@0 | 94 | |
| michael@0 | 95 | #endif /* !defined(mozilla_dom_MediaQueryList_h) */ |
